Treatment of textiles and other shaped articles made of cellulose derivatives



Patented Man 10,1942

UNITED STATES PATENT OFFICE TREATMENT OF TEXTILES AND OTHER SHAPED ARTICLES MADE OF CELLULOSE DERIVATIVES Henry Dreyfus, London, England, assignor to Celanese Corporation at America, a corporation of a No Drawing. Application January 25, 1941,Se-

rial No. 375,958. In Great'Britain January 19,

3 Claims. (CL 8-129):

This invention is concerned with improvements in or relating to the treatment oi textiles and other shaped articles, e. g. films, and especially articles having a basis oi cellulose acetate or the radicle of propionic or butyric acid, and the higher aliphatic monocarboxylic acid radicle may, for example, be the radicle oi caproic acid or caprylic acid but is preferably that oi laurlc'acid or a higher homologue thereoi, for example pale mitic or stearic acid. The reaction probably involves the formation oi the mixed anhydride oi the two types of acids. An esteriflcation medium containing an organic non-solvent liquid and a low concentration oi such a mixed anhydrlde which has previously been prepared and isolated mayalsobeused. I

It has been iound'that esteriiication by the process oi the present invention gives much better results than when there is no non-solvent liquid present or when a higher aliphatic acid halide is employed, since in general this reduces the breaking strength oi the articles very considerably.

The process is particularly valuable ior the treatment oi materials made oi acetone-soluble cellulose acetate or other lower iatty acid ester oi cellulose, e. g. cellulose propionate or butyrate. 'lhematerialstreatedmaybeyarnsinhankor other package iorm, e. g. hanks oi ordinary,

stretched or stretched and shrunk cellulose ace tate yarns, woven, knitted or other iabrics, ioiis, films or similar articles. it

The treatment may be eflected by introducing the materialsintoamediumcontainingamixture oi a lower aliplmtic monocarboxylic acid andoitheanhydrideoiahigheraliphaticmono-' earboxylic acid or, alternatively, oi the higher andtheonhydrideoitheloweracidand anhydride may be iormed inthepresence materials, but preierably they are introduced mto amedium containing the mixed anhydrkie. This'maybeiormedbyheatingasolumedium throughout the reaction, e. g. a volume-ratio of liquid which is a non-solvent for the materials for a time, e. g. minutes to 1 hour, so as to form the mixed anhydride and drive of! any lower monocarboxylic acid iormed or present in excess. 7

In general, better results are obtained ii the esterification medium is free or substantially free irom lower monocar-boxylic acid and is maintained free during the reaction by allowing any such acid iormed to distil over.

The reaction is carried out at a temperature of at least C. and particularly at a temperature oiabout C. Temperatures above or V are not in general necessary. The esterification medium should contain only a low concentration oi the esteriiying agents, for example a total concentration of about 5-10% of organic acid radicles dissolved in an organic liquid which is a non-solvent ior the materials. It is important that a high volume ratio oi esteriiying to materials should be maintained 50:1 or 100:1. Preierably the non-solvent liquid has a boiling point approximately the same as the reaction temperature to be employed, so that the reaction can be carried out at the boiling point, which simplifies temperature control. Xylene has been iound to be very suitable ior this purpose while other liquids which may be employed are toluene and kerosene. The treatment oi the materials is preierably continued until an increase in weight oi irom about 540% x the invention:

heating medium, in which case thecto or somewhat more has been obtained and in general this requires about 2-6 hours, for example 4 hours. I

The following example is given to illustrate Example Fabric made oi acetone-soluble cellulose acetate yarn is boiled ior 2-4 hours in an esteriiication medium prepared by boiling a mixture oi 5% oi stearic acid, 1% oi acetic anhydride and 04% oi xylene ior about 1 hour. The heating both during the preparation oi the esteriflcation medium and during the treatment oi the materials is carried out under such conditions that acetic acid iormed is distilled over and condensed. The volume ratio oi medium to materials is about 50:1. The heated iabric is thoroughly washed with carbon tetrachloride and dried.

By the process oi the present invention it is possible so to improve the water-prooi properties on an untreated cellulose acetate iabric under tion oi an'acid and ananhydride in an organic as certain conditions it passes through it immediately, when thetreated fabric is subjected to a similar test the water does not pass through for over two minutes. Again, the water-proof properties of a hose made of cellulose acetate yam may be improved so that when a quantity of water is put inside the water does not pass through the hose until pressure is applied and even then it does not wet the yarns.

Having described my invention, what I desire to secure by Letters Patent is:

1. Process for the treatment of textile materials, foils, films and the like having a basis of an organic derivative of cellulose, which comprises heating said materials at a temperature of at least 100 C. until the water-proof properties of said materials are improved, in an esteriiica tion medium which has substantially no solvent action on the base of said materials and which contains an organic liquid which has substantially no solvent action on the base of said materials, a compound having a lower aliphatic mono-carboxylic acid radicle containing at most 4 carbon atoms and a compound having a higher aliphatic mono-carboxylic acid radicle containing at least 6 carbon atoms, the total concentration of said acid radicles being from to 10% and at least one of the latter two compounds being present as an anhydride, the volume-ratio of esterifi'caaerane prises heating said materials at a temperature of at least 100 C. until the water-proof properties of said materials are improved,-in an esteriflcation medium which has substantially no solvent action on the :base of said materials and which contains an organic liquid which has substantially no solvent action on the base of said mate= rials, a compound having a lower aliphatic mono= carboxylic acid radicle containing at most 4 carbon atoms and a compound having a higher aliphatic mono-carboxylic acid radicle containing at least 6 carbon atoms, the total concentration of said acid radicles being from 5 to 10% and at least one of the latter two compounds being present as an anhydride, the volume-ratio of esterification medium to materials being at least :1.

3. Process for the treatment of textile materials, foils, films and the like having a basis of an acetone-soluble cellulose acetate, which comprises heating said materials at a temperature of at least C. until the water-proof properties of said materials are improved, in an esterification medium which has substantially no solvent action on the base of said materials and which contains xylene, acetic anhydride and stearic acid, the total concentration of the acetic and stearic acid radicles being from-5 to 10% and the volume-ratio of esterification medium to materials being about 50:1.

HENRY DREYF'US. 

